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Physician modification of Gore C3 excluder endograft for treatment of abdominal aortic aneurysms anatomically unsuitable for conventional endovascular repair

2014; Elsevier BV; Volume: 59; Issue: 6 Linguagem: Inglês

10.1016/j.jvs.2013.12.027

1097-6809

Amy Coulter, Tze‐Woei Tan, Wayne W. Zhang,

Cardiac, Anesthesia and Surgical Outcomes

Until recently, the Cook Zenith aortic endograft (Cook Medical Inc, Bloomington, Ind) was the only device used for physician-modified fenestration because its constraining wire allowed physicians to reconstrain the device after modifications. Although the Cook Zenith fenestrated endograft has been approved by the Food and Drug Administration, it is currently not available in the majority of the hospitals and is not applicable to the patients who need urgent or emergent aneurysm repair. With the redesign of the Gore C3 delivery system, the Gore Excluder aortic stent graft (W. L. Gore & Associates, Inc, Flagstaff, Ariz) can now also be reconstrained, which makes it suitable for physician-modified fenestration. We describe the technique for modification and implantation of the Gore Excluder aortic stent graft in a patient requiring 2-vessel bilateral renal artery fenestration. This application provides an additional option for treatment of patients with abdominal aortic aneurysms who are anatomically unsuitable for conventional endovascular aneurysm repair and are at high risk for open repair. Until recently, the Cook Zenith aortic endograft (Cook Medical Inc, Bloomington, Ind) was the only device used for physician-modified fenestration because its constraining wire allowed physicians to reconstrain the device after modifications. Although the Cook Zenith fenestrated endograft has been approved by the Food and Drug Administration, it is currently not available in the majority of the hospitals and is not applicable to the patients who need urgent or emergent aneurysm repair. With the redesign of the Gore C3 delivery system, the Gore Excluder aortic stent graft (W. L. Gore & Associates, Inc, Flagstaff, Ariz) can now also be reconstrained, which makes it suitable for physician-modified fenestration. We describe the technique for modification and implantation of the Gore Excluder aortic stent graft in a patient requiring 2-vessel bilateral renal artery fenestration. This application provides an additional option for treatment of patients with abdominal aortic aneurysms who are anatomically unsuitable for conventional endovascular aneurysm repair and are at high risk for open repair. Endovascular repair is increasingly becoming the preferred approach for repair of infrarenal abdominal aortic aneurysm.1Schwarze M.L. Shen Y. Hemmerich J. Dale W. Age-related trends in utilization and outcome of open and endovascular repair for abdominal aortic aneurysm in the United States, 2001-2006.J Vasc Surg. 2009; 50: 722-729Abstract Full Text Full Text PDF PubMed Scopus (191) Google Scholar However, some patients do not meet criteria for conventional endovascular repair because of unfavorable neck anatomy or inadequate proximal seal zone.2Carpenter J.P. Baum R.A. Barker C.F. Golden M.A. Mitchell M.E. Velazquez O.C. et al.Impact of exclusion criteria on patient selection for endovascular abdominal aortic aneurysm repair.J Vasc Surg. 2001; 34: 1050-1054Abstract Full Text Full Text PDF PubMed Scopus (270) Google Scholar Patients with low and moderate risk profiles as defined by their medical comorbidities may tolerate open repair, but high-risk patients have significantly increased mortality rates, which range from 2%-14%.3Steyerberg E.W. Kievit J. de Mol Van Otterloo J.C. van Bockel J.H. Eijkemans M.J. Habbema J.D. Perioperative mortality of elective abdominal aortic aneurysm surgery: a clinical prediction rule based on literature and individual patient data.Arch Intern Med. 1995; 155: 1998-2004Crossref PubMed Scopus (185) Google Scholar Debranching of the visceral aorta with subsequent aortic stent grafting and placement of stent grafts into the visceral branches alongside the main body aortic endograft ("snorkel" or "chimney" techniques) are used to decrease morbidity and mortality rates in high-risk patients.4Greenberg R.K. Clair D. Srivastava S. Bhandari G. Turc A. Hampton J. et al.Should patients with challenging anatomy be offered endovascular aneurysm repair?.J Vasc Surg. 2003; 38: 990-996Abstract Full Text Full Text PDF PubMed Scopus (320) Google Scholar Some specialty centers are using commercially produced branched or fenestrated aortic endografts.5Greenberg R.K. Sternbergh 3rd, W.C. Makaroun M. Ohki T. Chuter T. Bharadwaj P. et al.Intermediate results of a United States multicenter trial of fenestrated endograft repair for juxtarenal abdominal aortic aneurysms.J Vasc Surg. 2009; 50: 730-737Abstract Full Text Full Text PDF PubMed Scopus (292) Google Scholar, 6Verhoeven E.L.G. Vourliotakis G. Bos W.T.G.J. Tielliu I.F.J. Zeebregts C.J. Prins T.R. et al.Fenestrated stent grafting for short-necked and juxtarenal abdominal aortic aneurysm: an 8-year single-centre experience.Eur J Vasc Endovasc Surg. 2010; 39: 529-536Abstract Full Text Full Text PDF PubMed Scopus (314) Google Scholar However, these are not widely available in the United States, and customization of grafts requires up to 6-8 weeks.7Oderich G.S. Ricotta 2nd, J.J. Modified fenestrated stent grafts: device design, modifications, implantation, and current applications.Perspect Vasc Surg Endovasc Ther. 2009; 21: 157-167Crossref PubMed Scopus (106) Google Scholar, 8Starnes B.W. Physician-modified endovascular grafts for the treatment of elective, symptomatic, or ruptured juxtarenal aortic aneurysms.J Vasc Surg. 2012; 56: 601-607Abstract Full Text Full Text PDF PubMed Scopus (114) Google Scholar The technique for physician modification of stent grafts with the use of commercially available Z stent grafts has been described in detail previously.9Oderich G.S. Diameter-reducing wire to facilitate deployment of a modified Zenith fenestrated stent graft.Ann Vasc Surg. 2010; 24: 980-984Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar Reconstraining a stent graft after deployment is the critical feature. The ability to partially deploy and subsequently reconstrain the Gore C3 Excluder aortic stent graft (W. L. Gore & Associates, Inc, Flagstaff, Ariz) has made this an attractive option for physician-modified endovascular aneurysm repair. The patient was a 66-year-old man who had a 5.6-cm juxtarenal abdominal aortic aneurysm. He was at high risk for open repair because of severe chronic obstructive pulmonary disease and coronary artery disease. Food and Drug Administration (FDA)-approved Zenith fenestrated (Cook Medical Inc, Bloomington, Ind) endovascular device was not available at our institution. The risks and benefits of different treatment options, including open aneurysm repair, conservative medical management, and endovascular repair with physician-modified stent grafts, were discussed with the patient; he fully understood that fenestrated endovascular aneurysm repair with physician-modified stent grafts was off-label use and consented to proceed with the procedure. This case was a compassionate use without investigational device exemptions. Follow-up computed tomographic angiography (CTA) at 1 month and aortography at 3 months, while having carotid stenting for symptomatic carotid stenosis, showed no evidence of endoleak or renal artery stenosis. Follow-up with CTA every 6 months is planned. The distance to the visceral branches from the superior extent of the landing zone and size of the branch orifices were identified by means of centerline analysis on CTA. Axial images were used to identify the position of the branch vessels by use of clock-face orientation (Fig 1). Endograft modification was performed under strict sterile conditions on a back table. The valve of a 20F DrySeal sheath (W. L. Gore & Associates, Inc) was cut off. The sheath was cut to the size corresponding to the length of the main body endograft and then loaded onto the delivery system to reconstrain the device after modification. A Gore C3 Excluder aortic endograft was unsheathed until the contralateral gate was released, leaving the ipsilateral limb constrained. The locations for the fenestrations were pre-marked on the body of the stent graft by use of the measurements obtained from the centerline analysis on CTA (Fig 2). The fenestrations were made with a No. 11 blade and then were reinforced with the use of a wire from an EnSnare (Merit Medical, South Jordan, Utah), which was sutured circumferentially with running 5-0 Prolene (Fig 3).Fig 3Fenestrations are reinforced by suturing EnSnare wire (Merit Medical, South Jordan, Utah) circumferentially with 5-0 Prolene (A and B). Fenestrations are then precannulated through the contralateral gate with V-14 wires (C).View Large Image Figure ViewerDownload Hi-res image Download (PPT) The fenestrations were then precannulated with V-14 wires. Two V-14 wires were inserted into the main body through contralateral gate and pulled out from the fenestrations separately. The distal ends of the wires were then passed through the 20F DrySeal sheath, which was placed onto the shaft of the delivery system before deployment for modification. The stent graft was then re-loaded retrogradely into the DrySeal sheath (Fig 4). Umbilical tape and 0-0 silk ties were used to collapse the stents for reloading. The right femoral access was used for introduction of the main body and the left femoral access for placement of the contralateral limb. A 22F DrySeal sheath was introduced. The reconstrained main body was then introduced through the femoral sheath. A peel-away sheath was used to protect the V-14 wires from the sheath valve during insertion. The top of the main body was positioned just inferior to superior mesenteric artery (SMA) according to the lateral aortogram. The precannulated V-14 wires were used to selectively cannulate both renal arteries. This was confirmed by means of angiography, and the V-14 wires were then exchanged for Amplatz wires with a 1-cm flexible tip (Boston Scientific, Boston, Mass). After access of both renal arteries was achieved, the aortic endograft was deployed and the proximal seal zone was fully expanded with a Q50 balloon (W. L. Gore & Associates, Inc) (Fig 5). Two iCast covered stents (Atrium Medical, Hudson, NH) were deployed into both renal arteries and flared proximally with an 8-mm angioplasty balloon (Fig 6). The contralateral gate was then cannulated, and the contralateral limb was deployed in the standard fashion. The completion angiogram demonstrated patency of the SMA, both renal arteries, and no evidence of any endoleak. This was confirmed on follow-up CTA 1 month after the procedure (Fig 7).Fig 6Stent grafts are deployed in the renal arteries (A). After deployment, the stent grafts are flared within the main body aortic endograft with the use of an 8-mm angioplasty balloon (B). Two thirds of the branch stent grafts should be within the branch vessel, with one third extending into the aortic endograft.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig 7Follow-up computed tomographic angiography (CTA) at 1 month shows patency of superior mesenteric artery (SMA) and bilateral renal arteries with no evidence of endoleak.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The technique of C3 Excluder fenestration was originally described and presented by Dr Gustavo Paludetto from Brazil at the Vascular Interventional Advances (VIVA), 2012, in Las Vegas, Nevada. According to PubMed search, no case has been published previously. The steps for Gore C3 Excluder modification are summarized in the Table.TableSteps for physician modification of Gore Excluder endograft with C3 delivery system1. Preoperative planning with the use of three-dimensional reconstruction of CTA and centerline analysis.2. DrySeal sheath preloaded onto delivery system. Endograft is partially deployed.3. Fenestrations are made by sharply incising the ePTFE and reinforced by circumferentially suturing a cut EnSnare wire.4. Fenestrations are precannulated with V-14 wires through the contralateral gate.5. Endograft is reconstrained and loaded into cut DrySeal sheath.CTA, Computed tomographic angiography; ePTFE, expanded polytetrafluoroethylene. Open table in a new tab CTA, Computed tomographic angiography; ePTFE, expanded polytetrafluoroethylene. The fenestrated Gore C3 Excluder stent graft was pre-tested in vitro with the use of a demo device. To prevent tearing of expanded polytetrafluoroethylene (ePTFE) membrane, we sutured a piece of EnSnare wire around the edges to reinforce the fenestrations and make them visible under fluoroscopy. Long-term follow-up is needed for durability evaluation. Reformatting of the preoperative CTA that allows for centerline analysis is mandatory to ensure accurate positioning of the fenestrations. The sealing zone of the aneurysm should have a length of at least 15 mm above the highest renal artery and must be free of extensive calcification. Additionally, in the event that brachial artery access is required (eg, for patients with challenging "downward-angled" branch vessels), a 7F sheath is usually required as opposed to the 12F sheath described in modification of the Zenith endograft.7Oderich G.S. Ricotta 2nd, J.J. Modified fenestrated stent grafts: device design, modifications, implantation, and current applications.Perspect Vasc Surg Endovasc Ther. 2009; 21: 157-167Crossref PubMed Scopus (106) Google Scholar The presence of stent struts in the middle of the fenestrations may interfere with placement of covered stents into the renal or visceral vessels. To minimize the need to remove stent struts, all fenestrations should be marked on the main body of the endograft before making any cuts in the ePTFE. The positions of the fenestrations can be rotated a few degrees clockwise or counterclockwise synchronously until the positions are found in which the minimum number of stent struts are removed. The fenestrations might not be perfectly round, but it should not impede the accurate placement because the fenestrations are prewired with V-14, and this facilitates renal artery cannulation. Care must be taken not to incorporate the reconstraining suture for the aortic stent graft when suturing the snare wire. The use of a Freer elevator to collapse the anchors is helpful to facilitate complete reloading. The relatively short main body length of C3 Excluder devices is a concern for maintaining an adequate landing zone. The main body length is 4 cm in the 23-, 26-, and 28-mm devices; 5 cm in the 31-mm device; and 6 cm in the 35-mm device. In the majority of patients, the longitudinal distance between bilateral renal arteries is 2 cm or SMA fenestration is needed for suprarenal aneurysm, the working length of a 4-cm main body may not be long enough, unless 31-mm or 35-mm devices with longer main body are used. In this case, the positions of the renal arteries were identified by means of the clock-face orientation technique. Arc lengths were not calculated because the patient's abdominal aorta at the level of the renal arteries was not dilated and bilateral renal arteries were in the straight lateral direction. In general, arc length calculation is recommended if the accuracy of renal artery localization is concerned. If the DrySeal sheath is not long enough, the ability of reconstraining main body of the C3 Excluder device allows physicians to push the stent graft out of the sheath partially deployed and advance it into the aorta above renal arteries. Physicians can also fully open and partially or completely reconstrain the main body to make adjustments accommodating the fenestrations to renal arteries. After renal arteries are cannulated, the aortic stent graft must be deployed and ballooned before placement of the branch-covered stent to prevent crushing the portion of the branch-covered stent extending into the main endograft. Although the Cook Zenith fenestrated endograft has been approved by FDA, it is not applicable to the patients who need urgent or emergent aneurysm repair. On the basis of the advisory statement on clinical use of modified aortic endografts from the Society for Vascular Surgery,10White R.A. Advisory statement on clinical use of modified aortic endografts from the Society for Vascular Surgery.J Vasc Surg. 2013; 57: 832-833Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar Gore C3 Excluder fenestration may be performed as an alternative procedure for compassionate use in high-risk patients and in urgent or emergent cases when FDA-approved fenestrated endografts are not available. However, we would like to make it clear that this technique is not FDA-approved. Although each fenestration is reinforced with a piece of wire and 5-0 Prolene sutures, endoleak may develop if degeneration of the fenestrations in ePTFE graft occurs after long-term hemodynamic stress.